Stain system for membrane filters

ABSTRACT

A stain system for staining membrane filters including a stain basket for securely holding and carrying a plurality of membrane filters each supported in a filter assembly which provides substantial circumferential support for the filters and which is of a simple two piece construction which can be easily assembled and taken apart.

United States Patent [1 1 Doman et al.

[ Oct. 30, 1973 1 STAIN SYSTEM FOR MEMBRANE FILTERS [75] Inventors:Patrick A. Doman, Farmington;

Ronald N. Wilkie, New Baltimore,

both of Mich.

[731 Assignee: Gam Rad, Incorporated, Detroit,

Mich.

[22] Filed: July 25, 1972 [21] Appl. No.: 274,980

[52] US. Cl 118/503, 29/229, 224/45 K [51] Int. Cl. B05c ll/l4 [58]Field of Search ..118/500503,

[5 6] References Cited UNITED STATES PATENTS 2,344,855 3/1944 Dorfan118/501 2,522,416 9/1950 Weiskopf 118/503 2,635,784 4/1953 Bering et al55/509 X 3,362,141 l/1968 Royster, Jr. et al. 55/502 X 3,461,842 8/1969Conrad et al 118/500 3,486,631 12/1969 Rodman 118/500 X 3,543,66812/1970 Vlock 118/500 X FOREIGN PATENTS OR APPLICATIONS 728,946 12/1942Gennany 118/503 Primary ExaminerMorris Kaplan AttorneyJoseph R. Papp[57] ABSTRACT A stain system for staining membrane filters including astain basket for securely holding and carrying a plurality of membranefilters each supported in a filter assembly which provides substantialcircumferential support for the filters and which is of a simple twopiece construction which can be easily assembled and taken apart.

14 Claims, 5 Drawing Figures STAIN SYSTEM FOR MEMBRANE FILTERS SUMMARYBACKGROUND OF THE INVENTION The present invention relates to pathologyspecimens, such as body fluids and the like, staining apparatus, systemsand processes and more specifically to apparatus, systems and processesfor staining pathology specimens carried by a membrane filter.

In assisting pathologists and other medical practitioners in medicalanalysis and diagnosis it is often helpful to have pathology specimensstained to assist in identifying certain features or characteristics ofthe specimen. Pathology specimen staining techniques are well known andcan be performed by hand or automatically by devices such as thestaining machine shown and described in the US. Pat. No. to Kobernick,3,302,607, issued Feb. 7, 1967. In the staining process the tissuesamples are immersed in various baths and washes for preparationpurposes and are eventually stained in a stain bath. In many casespathology specimens such as samples are mounted to slides and the slidesare carried in a basket for processing. Some pathology specimens,however, such as urine are not readily carried by slides and aredeposited on membrane filters. The problem is in carrying the membranefilter through the various baths. In some cases the filter has beenclipped to a slide for processing; this, however, is unsatisfactorysince the filter is not securely retained thereby and can be damagedresulting in damage to the specimen. In addition the existing stainbaskets are not of a design to accommodate any substantial number ofslides having filters clipped thereto. In the present invention novelapparatus has been provided for processing membrane filters carryingspecimens which apparatus can be used in a manual or automaticprocessing system. Therefore it is an object of the present invention toprovide novel apparatus of the above described type. It is anotherobject to provide novel apparatus such as a novel basket structure forcarrying membrane filters held in a novel, simple two piece filtersupport for which the basket is specifically adapted. In addition it isanother object to provide other apparatus to assist in the assembly anddisassembly of the membrane filter to the filter support. It is anotherobject to provide a basket specifically adapted as noted above andfurther constructed such as to be compatible for use with an automaticstaining machine or with a removable handle for manual processing.

Other object, features, and advantages of the present invention willbecome apparent from the subsequent description and the appended claims,taken in conjunction with the accompanying drawing, in which:

FIG. 1 is an exploded pictorial view of a membrane filter with a filtersupport in relationship with a disassembly tool;

FIG. 2 is a pictorial view of the membrane filter and filter support ofFIG. 1, as assembled together and located on the disassembly tool;

FIG. 3 is an enlarged elevational view with some parts shown in sectiongenerally along the lines 33 in FIG. 2 and with some parts shown brokenaway;

FIG. 4 is an enlarged pictorial view showing a plurality of membranefilters in assembly with filter supports which are mounted in a basketfor processing; and

FIG. 5 is a pictorial view showing a plurality of membrane filters inassembly with filter supports, of a modified construction, and someparts shown broken away and which are mounted in a modified basket forprocessing.

Looking now to the drawings, a filter support assembly 10 includes anannular support member 12 of a circular shape which has a centralopening 14 defined by an annular recess 16. The support member 12 has anannular circular lip 18 which serves a purpose to be described. Therecess 16 is of a depth to receive a circularly shaped membrane filter20. A fiat, split retainer ring 22 has a relaxed outer diameter largerthan the diameter of recess 16 such that the split ring 22 whencompressed can be inserted in the recess 16 and can expand to securelyhold the filter 20.

Note that with the construction shown and described the filter 20 issecurely held for substantially its entire periphery or forsubstantially 360. Note also that the radial width of the recess 16(i.e. dimension x) is a minimum in order that as little of the filter 20be covered. In other words the present design provides good peripheralretention of the filter 20 while maintaining the exposed area at amaximum; in a preferred form of the invention the radial width was 0.125inch where the diameter of the recess 16 was 1.850 inch.

The thickness of the split ring 22 is relatively small and is preferablyless than the axial depth of the recess 16 such that when the split ring22 is inserted in recess 16 with a filter 20 therein the split ring 22will be flush with the outer surface of lip 18. The radial width y ofthe split ring 22 is slightly greater than the width x of the recess 16;this serves a purpose to be seen.

After processing the filter 20, it is desirable to remove the filter 20from the support assembly 10. The assembly 10 can be disassembled andthe filter 20 removed, without damage to the filter 20 by a separatingtool 24.

The tool 24 has an enlarged base 26 with a boss 28 extending upwardlytherefrom. The boss 28 is circular and of a diameter which is slightlyless than the diameter of the opening 14 in support member 12. To removethe filter 20 from the support assembly 10, the assembly I0 is placed onthe tool with the recess side facing up and with the opening 14 locatedover the boss 28. The split ring 22, having a width y greater than thewidth x of recess 16, will have an inside diameter less than the opening14. This is provided to a preselected extent such that the split ring22, when assembled in opening 14, will interfere with the boss 28. Thusby merely moving the support member 12 down overthe boss 28 the splitring 22, by engagement with the boss 28, will be removed and the filter20 will be deposited upon the flat upper surface of boss 28.

The filter 20 as secured to the assembly 10 can be processed in a basket30. The basket 30 is generally rectangularly shaped and has a pair ofrectangular end frames 32 and 34. A pair of upper rails 36 and 38connect the upper ends of the end frames 32 and 34 while a pair of lowerrails 40 and 42 connect the bottom of the end frames 32 and 34 atlocations in from their lower ends. The rails 36 and 38 are providedwith uniform grooves 44 and 46 which are in confrontation with eachother. Likewise the rails 40 and 42 are provided with grooves 48 and 50which are in confrontation with each other. Individual ones of thegrooves 44, 46, 48 and 50 are in alignment for a purpose to be seen.

The upper rails 36 and 38 are spaced apart such that the spacing betweenassociated grooves 44 and 46 is slightly greater than the outsidediameter of the support member 12 as defined by the annular lip 18. Thewidth of the grooves 44 and 46 is sufficient to receive the lip 18. Thelip 18 also fits into the associated ones of the grooves 48 and 50 inmore closely spaced lower rails 40 and 42. Thus the assembled supportassembly 10 with filter 20 can be securely held in the basket 30 via oneassociated set of the grooves 44, 46, 48 and 50. The distance of teethbetween grooves 44, 46, 48 and 50 is sufficient to properly space thegrooves 44, 46, 48 and 50 such that a plurality of assemblies such asassembly 10 can be located in consecutive ones of the grooves 44, 46, 48and 50 while still maintaining adequate clearance between adjacent onesof the assemblies, such as assembly 10, to permit good flow and accessof the necessary bath materials to the membrane filter 20. Note that byproviding the assembly 10 to be supported by a thin lip 18, which isless than the total axial thickness of the assembly 10, the number ofassemblies 10 that can be carried by the basket 30 can be maximized.Note also that the basket 30 is of a generally open structure formedonly of the frames and rails shown; this provides adequate support whileminimizing any impedance to fluid flow.

In order to facilitate use of the basket 30 on a staining machine suchas that shown in the Kobernick patent, supra, a plurality of verticalarms 52, 54 and 56 are provided. Vertical arms 52 and 54 are located atopposite ends of frame 32 while arm 56 is located in the center of theopposite frame 34. The arms 52, 54, and 56 each have tabs with the tabsfor arms 52, 54 extending to opposite sides of basket 30 and the tab forarm 56 extending away from the frame 34. These tabs permit gripping forprocessing by a staining machine or by a handle (shown in phantom)whereby the basket 30 can be processed manually.

A modified form of the invention is shown in FIG. 5 where componentssimilar to like components in the embodiment of FIGS. 1-4 have beengiven the same numeral designation with the addition of the letterpostscript a.

Looking now to FIG. 5, a filter support assembly a includes an annularrectangularly shaped support member 12a which has a central opening 14adefined by a annular, circular recess 16a. The support member 120 has aperipheral lip 18a. Like the embodiment of FIGS. l-4, the recess 16a isof a depth to receive a circularly shaped membrane filter 20a. A flat,split retainer ring 220 is like ring 22 and performs the same functionas ring 22 and hence can be inserted in the recess 16a to securely holdthe filter 20a. I

Again the thickness of the split ring 22a is relatively small and ispreferably less than the axial depth of the recess 16a such that whenthe split ring 22a is inserted in recess 16a with a filter 20a thereinit will be flush with the outer surface of lip 18a. As with theembodiment of FIGS. 1-4 the axial width (y) of the split ring 22a isslightly greater than the width (x) of the recess 16a.

After processing the filter 20a, it can be removed from the supportassembly 10a in the same manner as with FIGS. l-4 by the separating tool24.

The filter 20a as secured to the assembly 10a can be processed in abasket a. The basket 30a is generally rectangularly shaped and has threeframe members 60, 62 and 64. The three frames 60, 62 and 64 are heldtogether and verticallyspaced by post structure 66. The frames 60 and 62are identical and each has grooved cross rails 68, and 72 and 74, 76 and78, respectively. The cross rails 68 and 70 and 70 and 72 are providedwith uniform grooves which are in confrontation with each other.Likewise the rails 76 and 76 and 76 and 78 are provided with grooveswhich are in confrontation with each other. Individual ones of thegrooves on rails 68 and 74, 70 and 76, and 72 and 78 are in verticalalignment.

The width of these grooves is sufficient to receive the lip 18a. Thusthe assembled support assembly 10a with filter 20a can be securely heldin the basket 30a via one associated set of these grooves. The distanceof teeth between these grooves is sufficient to properly space them suchthat a plurality of assemblies such as assembly 10a can be located inconsecutive ones of the groove sets while still maintaining adequateclearance between adjacent ones of the assemblies, such as assembly 10a,to permit good flow and access of the necessary bath materials to themembrane filter 20a. The lower frame 64 has intermediate cross rails 80and 82 upon which the assemblies 10a can rest for support.

As with the embodiment of FIGS. 1-4, by providing the assembly 10a to besupported by a thin lip 18a, which is less than the total axialthickness of the assembly 10a, the number of assemblies 10a, that can becarried by the basket 30a can be maximized. Note also that the basket30a is of a generally open structure formed only of the frames and railsshown; this provides adequate support while minimizing any impedance tofluid flow.

The basket 30a can be adapted for use on staining machine such as thatshown in the Kobernick patent.

Thus in the present invention a system has been shown and describedwhereby membrane filters can be easily handled and quickly processed.This system as shown and described includes singly and in combination anovel basket, a novel filter support assembly and novel apparatus forfacilitating removal of the filter after processing and disassembly ofthe support assembly.

While it will be apparent that the preferred embodiments of theinvention are well calculated to fulfill the objects above stated, itwill be appreciated that the invention is susceptible to modification,variation and change without departing from the proper scope or fairmeaning of the invention.

What is claimed is:

1. In a system for retaining tissue or the like comprising:

a disk-like filter for carrying said tissue;

a disk-like annular support member having a circular recessed portionfor completely receiving the filter and tissue thereon;

a relatively narrow inwardly extending flange disposed about one end ofsaid recessed portion for seating said filter;

a relatively narrow, interference fit, split ring element receivedentirely within said recess to retain the filter against said flange;and

said element having a radial width larger than that of said flange;

whereby said retained filter and tissue can be selectively exposed totreating fluids and whereby the portion of said retainer elementextending beyond said flange provides a sufficiently firm support forremoval of the tissue carrying filter, from the recessed portion, by aforcing member acting on the filter area aligned with said portion ofthe retainer element.

2. The apparatus of claim 1 wherein the radial width of said flange is0.125 inch and the recess diameter is 1.850 inches.

3. The apparatus of claim 2 wherein said disk-like member includes aradially extending flange element about the outer periphery thereof.

4. The apparatus of claim 3 wherein the disk-like member is circular inperipheral configuration.

5. The apparatus of claim 3 wherein the disk-like member is rectangularin peripheral configuration.

6. The apparatus of claim 1 in combination with a forcing tool having aperipheral portion adapted to overlie said aligned filter area wherebythe filter and tissue therewith may be removed from said recessedpostion.

7. The apparatus of claim 1 in combination with a basket means forsupporting a plurality of said disk-like members for simultaneouslytreating the filters therewith, said basket comprising:

an open frame means;

at least one pair of spaced upper rails and one pair of spaced lowerrails supported within said frame and generally parallel to one another;

each rail including consecutive, inwardly opening slots; and

said slots being in associated alignment and of adimension whereby eachopposed pairs of slots slidingly receives a peripheral portion of, andretains in a predetermined vertical position, one of said plurality ofdisk-like members.

8. The apparatus of claim 7 wherein said lower rails are closer to oneanother than the upper rails and provide the bottom support surface forsaid disk-like members.

9. The apparatus of claim 7 wherein each lower rail is in verticalalignment with the corresponding upper rail and is disposed at anintermediate vertical section of said frame; I

The frame is provided with at least an additional rail element at thebottom thereof; and

said disk-like members are supported on said additional rail element.

10. The apparatus of claim 7 wherein the frame is compartmented and eachcompartment includes said pairs of upper and lower rails to each supporta plurality of said disk-like members.

11. The apparatus of claim 7 including arm elements extending fromopposite ends of said frame and adapted to be associated with holdermeans whereby the basket may be manipulated in said system.

12. The apparatus of claim 11 wherein handle means are affixed to saidarms whereby to manipulate said basket. I

13. The apparatus of claim 11 including two of said arms at oppositeends of one of said end frame structures and one of said arms beinggenerally centrally located at the other of said end frame structures.

14. The apparatus of claim 13 having a tab element extending away fromsaid basket at the terminus of each of said arms.

1. In a system for retaining tissue or the like comprising: a disk-likefilter for carrying said tissue; a disk-like annular support memberhaving a circular recessed portion for completely receiving the filterand tissue thereon; a relatively narrow inwardly extending flangedisposed about one end of said recessed portion for seating said filter;a relatively narrow, interference fit, split ring element receivedentirely within said recess to retain the filter against said flange;and said element having a radial width larger than that of said flange;whereby said retained filter and tissue can be selectively exposed totreating fluids and whereby the portion of said retainer elementextending beyond said flange provides a sufficiently firm support forremoval of the tissue carrying filter, from the recessed portion, by aforcing member acting on the filter area aligned with said portion ofthe retainer element.
 2. The apparatus of claim 1 wherein the radialwidth of said flange is 0.125 inch and the recess diameter is 1.850inches.
 3. The apparatus of claim 2 wherein said disk-like memberincludes a radially extending flange element about the outer peripherythereof.
 4. The apparatus of claim 3 wherein the disk-like member iscircular in peripheral configuration.
 5. The apparatus of claim 3wherein the disk-like member is rectangular in peripheral configuration.6. The apparatus of claim 1 in combination with a forcing tool having aperipheral portion adapted to overlie said aligned filter area wherebythe filter and tissue therewith may be removed from said recessedportion.
 7. The apparatus of claim 1 in combination with a basket meansfor supporting a plurality of said disk-like mEmbers for simultaneouslytreating the filters therewith, said basket comprising: an open framemeans; at least one pair of spaced upper rails and one pair of spacedlower rails supported within said frame and generally parallel to oneanother; each rail including consecutive, inwardly opening slots; andsaid slots being in associated alignment and of a dimension whereby eachopposed pairs of slots slidingly receives a peripheral portion of, andretains in a predetermined vertical position, one of said plurality ofdisk-like members.
 8. The apparatus of claim 7 wherein said lower railsare closer to one another than the upper rails and provide the bottomsupport surface for said disk-like members.
 9. The apparatus of claim 7wherein each lower rail is in vertical alignment with the correspondingupper rail and is disposed at an intermediate vertical section of saidframe; The frame is provided with at least an additional rail element atthe bottom thereof; and said disk-like members are supported on saidadditional rail element.
 10. The apparatus of claim 7 wherein the frameis compartmented and each compartment includes said pairs of upper andlower rails to each support a plurality of said disk-like members. 11.The apparatus of claim 7 including arm elements extending from oppositeends of said frame and adapted to be associated with holder meanswhereby the basket may be manipulated in said system.
 12. The apparatusof claim 11 wherein handle means are affixed to said arms whereby tomanipulate said basket.
 13. The apparatus of claim 11 including two ofsaid arms at opposite ends of one of said end frame structures and oneof said arms being generally centrally located at the other of said endframe structures.
 14. The apparatus of claim 13 having a tab elementextending away from said basket at the terminus of each of said arms.